Poisoned by Massage

Rather than being “detoxifying,” massage may cause a modestly toxic situation in the body

I am a science writer and a former Registered Massage Therapist with a decade of experience treating tough pain cases. I was the Assistant Editor of ScienceBasedMedicine.org for several years. I’ve written hundreds of articles and several books, and I’m known for readable but heavily referenced analysis, with a touch of sass. I am a runner and ultimate player. • more about me • more about PainScience.com

Massage is toxic?

Probably a little bit, yes — technically. But so is scotch. And hard exercise.

SUMMARY

Massage is not a detoxification treatment in any sense, contrary to a popular belief. Ironically, it’s the opposite: post-massage soreness and malaise (PMSM) is probably caused by mild rhabdomyolysis (“rhabdo”). True rhabdo is a medical emergency in which the kidneys are poisoned by myoglobin from muscle crush injuries. But many physical and metabolic stresses cause milder rhabdo-like states — even just intense exercise can do it, and probably massage as well. This is substantiated by a case study of acute rhabdomyolsis caused by intense massage (see Lai), by many well-documented cases of exertional or “white collar” rhabdo, and by the strong similarity between PMSM and ordinary exercise soreness. A rhabdo cocktail of waste metabolites and by-products of tissue damage is probably why we feel a bit cruddy after biological stresses and traumas — even massage, sometimes. And you can’t “flush” the rhabdo away with massage or by drinking a little extra water. PMSM is just an unavoidable mild side effect of strong massage.

full article 4500 words

My title is provocative and sensational, yes — guilty! Despite that, I love massage therapy, and I think it’s a valid and valuable treatment for many painful problems. This is not an anti-massage article — it’s a fascinated by massage article. And it turns out that massage may be a little toxic. Just a teensy bit.

This actually shouldn’t come as any kind of surprise. Nor is it even much of a problem. But it is interesting, and — more importantly — it is contrary to popular notions. That makes it a perfect topic for PainScience.com.

The idea of “toxins” is often unethically exploited in alternative medicine, usually to sell detoxification treatments.1 So why am I writing about them now? I have argued that toxin talkers should either be specific when they talk about toxins, or stop talking about toxins.

I am going to be specific. And there’s not detox solution for sale here. (And I’m probably sacrificing a small fortune. Pesky ethics!)

PMSM = feeling a bit gross after massage

The massaged often suffer from varying degrees of mild soreness and malaise following a massage — post-massage soreness & malaise, or PMSM.23 The worst cases feel like a touch of the flu. PMSM has to be caused by something unpleasant.

Stronger massage tends to cause more PMSM — though the effect is as unpredictable as weather. The worst cases of post-massage malaise feel like a touch of the flu. It has to be caused by something unpleasant.It is often characterized by therapists as a necessary evil, a “healing crisis” that we must endure to get to the benefits on the far side. No pain, no gain is the (usually) unspoken message. And fairly often the effect is explained more specifically as the symptom of a healthy detoxification process with a (rather doubtful) happy result: unspecified toxins trapped in weary, tight muscles are freed and flushed from muscle, poisoning us mildly as they make their way out of the body via kidneys and livers. There are lot of problems with that mental picture, and they are discussed in detail in Should You Drink Water After Massage?

Ironically, not only is the flushing theory unsound, massage may not even be “liberating” toxins that were there when the client walked in the door. In fact, massage may be creating them — by-products of minor muscle injury. That would mean that massage is, if anything, actually a “toxifying” treatment, not a detoxifying one. (This is actually one of the original reasons for the idea that toxins need to be flushed out from the body by drinking some extra water.) If so, it’s ironic that the detox myth has turned itself inside out over the years. Few massage therapists have considered the possibility that the client leaves with a problem they didn’t arrive with. Unfortunately, it’s a strong possibility.

And it’s not such a radical idea. PMSM is real. Something icky is clearly going on after some massages. What?

Rhabdo the Terrible: a medical emergency (which has nothing to do with massage)

Rhabdo kills

But it turns your pee the colour of tea first: one of the signature signs. The fact that urine does not look like this a day after a massage is reassuring.

Rhabdomyolysis — or just “rhabdo” for short, and for the rest of this article — is a medical emergency that mostly crops up in the aftermath of horrible, crushing traumas.4 Rhabdo can kill, even when injuries are otherwise non-lethal. It is most often seen in the wild in the aftermath of earthquakes and car accidents. It was one of the (wrong) diagnoses suggested by Dr. House in a 2009 episode, “Known Unknowns.”

When muscle is injured, cellular guts are spilled into the blood, most notably myoglobin molecules, which messes with blood chemistry a bit, poison the kidneys, and turns your pee dark brown. If it gets to the point of kidney damage, it has to be treated with a lot of intravenous fluids to dilute the poisons in the kidneys — and there’s the “flushing” connection (and the first hint of anything to do with massage).

Rhabdo the Terrible, the medical emergency, really has nothing to do with massage. Be aware of this if you mention a connection to a doctor — you will get scoffed at.

But … what if there’s only a little myoglobin? What about mild rhabdo? Can massage cause mild, non-emergency rhabdo? Almost certainly, it turns out.5 In fact, if you get a strong enough massage, it can even — almost — cause severe rhabdo.

An extreme-massage horror story: a case of genuine rhabdomyolysis induced by massage, with kidney danger and everything

In 2006, an elderly gentleman collapsed with a fever and failing kidneys.6 There are any number of reasons that might happen to an 88-year-old man, but the diagnosis turned out to be a fairly clear cut case of rhabdomyolysis.7And there was a smoking gun of a cause. A veteran of regular massage for years, he’d had an unusually intense massage the day before. “Intense” is actually a bit of an understatement…

The afternoon before this accident, he received a body massage session for 2 h served by two new massagists [sic] at the same time instead of one. The strength of this massage session was significantly stronger than that of the past.

Safety tip: don’t get a brutal two-hour massage from a pair of “massagists.”

Clearly this was an exceptional massage. Nevertheless, assuming the rhabdo wasn’t caused by something else,8 his case demonstrates that massage probably can damage muscle. If he hadn’t actually collapsed, he still would have felt perfectly awful — in other words, he would have had wicked PMSM.

Disintegrating muscle tissue!

Rhabdo the Terrible is mostly defined by nasty muscle damage and kidneys dying from myoglobin poisoning — right before you die. It’s the kidney damage that particularly makes rhabdo a medical emergency. But there’s a lot of other things going on — a cocktail of substances that cause a lot of other symptoms (ahem, malaise) many hours before your kidneys are wounded.

Notably, frank trauma is not the only way to get rhabdo, just one of the worst and most obvious. Instructions for releasing lots of myoglobin into the blood:

Step 1: Physically crush muscle.

You’re done! But rhabdo is not just caused by “crushed” muscle but by muscle that, in the words of Wikipedia, “rapidly breaks down” … by any means.

Rhabdo the Merely Unpleasant (a.k.a. recreational rhabdo)

Read up on rhabdo and it becomes clear that while the worst cases are caused by things like buildings falling on people’s legs, there are plenty of other less traumatic causes:

a variety of unusual metabolic states

miscellaneous drugs, toxins, and infections

extended tissue compression (e.g. a long surgery)

both hypo and hyperthermia

and even just extreme exertion

What this odd list of causes tells us is that acute rhabdomyolysis is the tip of a physiological iceberg, the bad end of a broad spectrum.11 Muscles will obviously spill their chemical guts in response to much milder stresses and forces than overt crushing.

Relatively minor, exertional rhabdomyolysis is actually common, and even has a name: “white collar rhabdomyolysis.”12 That term was coined by Knochel in 1990 because rhabdo was striking recreationally extreme athletes — people who voluntarily work themselves into a sorry state.13Rhabdo often strikes recreationally extreme athletes, people who voluntarily work themselves into a sorry state. You could also call it (for fun) recreational rhabdo. Another well-known source of rhabdo cases is boot camp: “large numbers of [recruits] may have myoglobinemia….”14

After a bit of browsing through the literature, I have the impression that you could be rhabdo-ized by an especially hard sneeze.

These are real cases of rhabdomyolysis, with quantities of myoglobin in the blood ranging from worrisome to alarming, and plenty of mineral and electrolyte derangement — but they are also generally less severe and less likely to cause kidney damage. They are somewhere in the middle of the rhabdo spectrum.

This is also roughly where the older man landed on the spectrum after his brutal 2-man, 2-hour massage. That case is probably the worst case scenario for massage-induced rhabdo … but it’s also a pretty bad worst case scenario. If that’s what a strong two-hour massage can do, what can a strong one-hour massage do? Maybe to someone with a genetic predisposition to rhabdo?15

Mild rhabdo as a common denominator in feeling cruddy after virtually any physical stress

To understand common experiences, it is often helpful to learn about their extreme and exaggerated forms. What’s going on here? Turn it up! Acute rhabdo is interesting and revealing because it almost certainly represents the extreme form of a tamer and nearly universal human experience: feeling sore and cruddy after physical stress.

The lower half of the rhabdo spectrum is messy and fascinating. It is undoubtedly biochemically diverse, with the exact cocktail depending heavily on many variables like genes, fitness, and the type of stress. Regardless, if relatively normal people like runners and soldiers can get middlin’ rhabdo, then it is virtually guaranteed that less extreme stresses are fairly routinely causes of less extreme rhabdo. Much of this would fall well below the threshold of what would ever be diagnosed as rhabdomyolysis. Indeed, at the lowest end of the spectrum we simple have other names for it …

“Soreness,” for instance.

Rhabdo the Merely Unpleasant clearly overlaps — mostly or entirely — with the familiar phenomenon of being really sore after strong exercise (usually called DOMS, for delayed onset muscle soreness). And that, in turn, feels almost exactly like PMSM. Quite appropriately, one of the names for DOMS is “muscle fever.”

These experiences are probably just mild versions of something that can get a lot more dire, but usually doesn’t. But the nature of the mild phenomenon is nicely illuminated by the nature of its more serious versions. Although the biochemical details are absurdly complex, the general theme is not — we are poisoned by the by-products of relatively minor tissue stress.

Even a bit of massage.

So what? The implications are surprisingly unexciting

This is all very interesting, but it may not be very important.

As I mentioned at the start, “Poisoned By Massage” is a sensational title. I chose it to help promote the article, of course — but I wouldn’t have chosen it if I didn’t also believe that “poisoned by massage” actually is scientifically defensible (as well as provocative and interesting). I think the evidence and reasoning is good, and I have high confidence that massage actually does “poison” us, a little.

But so what? So does exercise! And we aren’t quitting that. It is nearly impossible to progress in fitness without “poisoning” yourself with a little DOMS, almost regularly. It is not entirely unreasonable to call it a “healing crisis” — an unpleasant price to pay for clear benefits.16

The issue with massage is that the benefits are much less clear. No one really knows exactly what good massage does for people, medically speaking.17 It’s rather murky. We don’t even know if it makes us “fitter” to adapt to the stress of PMSM. Good massage is intrinsically satisfying as a sensory experience, and that is probably a good enough reason to put up with some side effects.Being toughened up by massage might be as dubious as toughening up your feet so you can walk barefoot — that’s all fine and good, but do you need tough feet? Probably not.

Fortunately, we do know that good massage is intrinsically satisfying as a sensory experience, and that is probably a good enough reason to put up with some side effects. However, I am also sure that I don’t want to dial up the PMSM and embrace it either. It can mostly be avoided with gentler treatment, and probably should be.18

Life is stressful. It is a multi-decade process of adapting to stresses. I’m happy to tolerate a little mild rhabdo along the way — but I’m certainly going to try to minimize it.

Afterword: The flushing theory goes down the drain

This entire article started out as an attempt to clarify a point about “flushing” in my article Water Fever and the Fear of Chronic Dehydration. The effort got a little out of hand, and I ended up with a 3700-word article about rhabdomyolysis. However, I still need to address the flushing thing …

Photograph of a glass of water.

If PMSM is basically a light poisoning, does this validate the popular practice of advising massage clients to drink extra water? Mostly no — it’s not specifically, medically relevant.19 It’s sensible to avoid compound mild rhabdo with dehydration. But it’s sensible to avoid dehydration, period.

If acute rhabdo is treated with IV fluids, doesn’t that suggest that drinking water would help? In mild rhabdo, we’re not worried about kidney damage at all.20 And drinking an extra glass or two of water wouldn’t (remotely) do the job anyway. Indeed, there’s an ironic catch-22: if you drank enough water to successfully dilute a dangerous concentration of myoglobin in your kidneys, you’d actually poison yourself. With water.21

Consider: Can you “treat” the much more familiar problem of DOMS by drinking extra water? Answer: definitely not. Try drinking three extra, big glasses of water the next time you’re super sore after a big workout. Still really sore? You can count on it.

In principle, the only medical condition that can be effectively treated by drinking more water is … dehydration. A number of disease processes and even toxins are dehydrating, which can in turn be treated with hydration. The obvious example is alcohol.22 But neither massage nor rhabdomyolsis is “dehydrating.” The only medical condition that can be effectively treated by drinking more water is … dehydration.(I’ve actually heard the claim that massage is hydrating — but that’s too kooky to bother debunking.)

Dehydration is inherently dangerous, and will particularly aggravate any condition where the concentration of toxins in your body fluids is a factor, and this can be helped by diluting the toxin with a higher blood volume — but only a little, and not enough to dilute toxins.23 Acute rhabdomyolysis is treated with intravenous fluids because, again, you literally cannot drink enough to dilute the toxins enough to protect the kidney.24

Many people will guess that drinking makes you pee more, which means more kidney action, which means more processing and filtration of some blood borne toxins — but the logic is just the same as with blood volume. It’s true-yet-trivial.25

Dehydration is worth avoiding in itself, of course, and it’s not illogical to make sure you avoid it after a massage: who wants both pre-rhabdo and dehydration at the same time? Not me. Unfortunately, in no way is extra hydration really “protective” — there’s just not that much difference between hydrated and un-hydrated.

APPENDIX: Responses to criticisms

I certainly expected to be criticized for being “negative” about massage in this article — and I was criticized for it — but I was also called out for overconfidently presenting a theory without evidence. That’s ironic: I’ve put in plenty of time fighting hype about premature conclusions, and I would hate to be the source of one. Am I?

Whilst not disputing that your hypothesis may very well be correct and it is an interesting and plausible position, I feel that your conclusions are just a little strong without being backed by sufficient evidence.

“Inner West Mobile Massage” commenting on Facebook

I appreciated the spirit of that criticism, and I even agreed with it and immediately changed one key overconfident sentence in the conclusion. But as I reviewed this whole article looking for other signs of overconfidence, my concern eased. There are a lot of qualifiers and equivocation here! I say “maybe” a lot. It’s clear from the style that I’m theorizing, thinking out loud. I do like the theory, and I suspect it’s probably correct, but I don’t think I present it as a sure thing — nowhere close.

More criticisms arrived. On Twitter, for instance, @SwoleClient accused me of “unfounded claims,” arguing that I was basing my entire argument on a single case study. Others echoed the sentiment.

I do not agree with that. There are two main issues here:

confusion about what a “claim” is, and where the burden of proof is

levels of confidence and evidence

“Claim” need not apply here

A claim is any unverified assertion. But not all claims are created equal. In health care and health science, “claim” implies a more self-serving assertion. If a claim could be used as a bullet-point in a sales pitch, it’s more claim-y. If it makes you (or your profession) look better, it’s more claim-y. And the more claim-y it is, the more it needs to be backed up.

This special case of the word claim comes from the thorny ethical challenges with selling care to sick, hurt people. All claims need critical appraisal and verification, but it’s just not as ethically critical if it has no claim-stink. Sagan’s idea that “extraordinary claims require extraordinary evidence” is not just about alien abductions and lake monsters. It’s also, in spirit, about more mundane but self-serving and profitable claims — a more common ethical hazard than truly extraordinary claims.

I presented my theory to cast doubt on classic self-serving claims, claims that serve the interests of massage therapists: the popular and specific claim that massage “detoxifies,” and the more general claim that massage is beneficial (or at least safe). The “claim” that I made in Poisoned by Massage is more self-defeating than self-serving. I could probably make much more money just by shutting up about things like this.It superficially contradicts my widely published opinion that people should purchase massage services and devote considerable energy to self-massage (although I explain in the article that it’s not really much of a concern). My “negativity” about massage and many other treatments does great harm to my bottom line. I could probably make much more money just by shutting up about things like this.

So the accusation of “unfounded claim” doesn’t fit well — technically correct, but definitely wrong in spirit. What I presented is just a partially supported theory.

There is exactly no evidence whatsoever that massage detoxifies. But I presented some evidence and a plausible theory that it does, in fact, do just the opposite. This is more about putting a dent in the detoxification claim than proving my own hypothesis — my own case simply has to be “reasonable” to cast significant doubt on the claim.

Levels of confidence and evidence

Many professionals believe (or fear) that evidence-based medicine is uptight and narrow, and ignores their clinical experience (even though EBM has always emphasized that evidence is only one important factor in clinical reasoning).

Now, when I defend a theory with imperfect data, I got flak from some of the same people for not presenting enough evidence! Bah.

My case for rhabdo as the cause of post-massage soreness and malaise was not just based on a single case study, as several critics implied. I argued it from a few different angles, and supplied a fair bit of “circumstantial” evidence (indirect evidence). Chalk the whole thing up to “you based everything on one case study,” as a few people did, is a facile synopsis.

But neither did I say that the evidence was strong or that my conclusion is airtight. The level of evidence was modest, the reasoning reasonable — and my level of confidence matched it.

It’s a trap! An example

One crafty critic tried to trap me in an apparent inconsistency:

Earlier this year you complained that there wasn’t enough evidence for the claim that massage reduces inflammation. But now you’re claiming with weak evidence that massage causes rhabdo. What gives?

Here’s what gives: the researchers involved in that study made a big massage-boosting claim that was implausible to begin with in any number of ways, and which was poorly supported by extremely indirect evidence. The claim was big, so the burden of proof was heavy, and yet all they had was some extraordinarily complex test tube evidence, full of problems, and far removed from any sound clinical implications. And yet they summed it up very confidently for the media and the journal very confidently as “massage reduces inflammation.”

Not the same thing.

A missed opportunity

There is something wrong with this article, but no one caught it: its most significant outstanding flaw is the absence of any discussion of alternative explanations for the phenomenon of post-massage soreness and malaise. “How else can I explain this?” is a pretty basic part of critical thinking, and it’s missing. I didn’t go there.

Maybe next month.

Notes

The idea of “toxins” is usually used as a tactic to scare people into buying de-toxifying snake oil. Exactly what substances and how they are to be removed is always vague, because the sellers are making it up. The body deals with unwanted molecules in many ways; the only truly detoxifying treatments help the body eliminate or disarm molecules the body cannot process on its own, like a stomach pump or an antivenom. Anything less, like mildly stimulate one normal excretion pathway in a sauna, is a detox scam. BACK TO TEXT

Cambron JA, Dexheimer J, Coe P, Swenson R. Side-effects of massage therapy: a cross-sectional study of 100 clients.J Altern Complement Med. 2007 Oct;13(8):793–6. PubMed #17983334. This study found that about 10% of people reported “some minor discomfort” the day after massages — which were fairly gentle, I presume. I doubt they would have tested painfully strong massage without mentioning the intensity. However, painfully strong massage is quite common “in the wild.” And the rate of soreness would likely go up sharply with the intensity. For contrast, a more general study of all kinds of manual therapy (see Carnes) found that 20-40% of treatments will cause some kind of unpleasantness, side effect or “adverse event” in medicalspeak. BACK TO TEXT

A few readers have challenged “often,” arguing that the phenomenon is rare. Therapists who have heard little about it from their own patients may simply be doing their jobs well: good massage is generally going to be gentle enough to avoid triggering post-massage soreness and malaise. Nevertheless, I assert that it is quite common — in large part because recklessly intense massage is also common. We’re not likely to ever get much hard data on this, so the true incidence is going to remain a mystery, but the 10–40% rates reported by Cambron and Carnes make me confident that PMSM is hardly “rare.” Even it’s only happening to one patient in 20, that would still a huge number of cases around the world every year. BACK TO TEXT

The key indicator molecule is creatine phosphokinase (CPK). Rhabdo is “official” when kidney damage starts around 20,000 U/I of CPK, and he had just about 8,000 around day 3 when it was first measured. It had probably peaked higher. BACK TO TEXT

I think that assumption is quite safe. It’s hardly guaranteed, of course. A single case study is always prone to misinterpretation. There are other causes of rhabdo, and elderly people have many vulnerabilities. If the rhabdo was caused by something else, then this could be a classic case of post hoc ergo propter hoc — the logical fallacy of assuming that something was caused by whatever event it follows, which is not necessarily so. But the fallacy is the assumption, and in fact causes do precede their effects. And here we have a specific effect with a likely cause immediately preceding it. BACK TO TEXT

Another weird, extreme case study paper (Tanriover) tells the horror story of one person’s awful experience with a severe reaction to infrared heat and regular massage over several days. The trouble started after several days. His neck and arms became swollen, the pain “unbearable,” and his “serum muscle enzymes were increased” — rhabdo? Some degree of it, very likely. The presence of rhabdo also implicates the massage itself as a significant mechanism of injury.

(It’s hard to imagine any sane amount of infrared heating causing such a horrible reaction, and I don’t think it would increase muscle enzymes in the blood under any circumstances. Heat exhaustion would, but that’s a more obvious threat that wasn’t even mentioned. As an interesting side note, some people also believe that infrared (and other) saunas are “detoxifying,” and yet here we have a case where it clearly failed to do that.)

Yes, they surely exist, of course — again, see Landau et al. In fact, I suspect I am one of those people — which is one reason why I’ve written this article. BACK TO TEXT

Clarification: I don’t think it’s correct to imply that the DOMS is actually part of or the cause of “healing.” There’s a fairly big ethical difference between telling someone, “This DOMS stuff is an unavoidable side effect” versus “DOMS is unpleasant, but it’s for your own good.” No. It’s just a price to pay. BACK TO TEXT

If mild rhabdo is indeed the cause of PMSM, the mechanism is probably just the circulation of a variety of molecules, all of which will have different processing pathways, and drinking extra water just has little or nothing to do with how fast that happens. In other words, hydration does not accelerate metabolic processing of a variety of miscellaneous molecules. BACK TO TEXT

This a perfect example of why you really need to know your biochemistry and get specific if you’re going to talk about toxins. Myoglobin itself is not toxic, and can circulate more or less harmlessly through your blood. It doesn’t become a problem until it dissolves in acidic urine in the kidneys, because one of its molecular parts poisons the kidneys on its way through. BACK TO TEXT

You would dilute everything else you need in your blood — and end up with water toxicity, which is just as dangerous. When you treat acute rhabdo, you have to flush the kidneys with lots of fluid, but also include a smart cocktail of electrolytes and glucose. Otherwise the cure is just as bad as the disease. BACK TO TEXT

Many of the symptoms of hangover are caused by dehydration. But not alcohol poisoning proper, which can kill but not be dehydration, and you can’t “flush” the alcohol from your system. The only way to prevent the poisoning is to throw up or pump out unabsorbed alcohol. BACK TO TEXT

Dehydration starts causing headaches and nausea at only about 5%, and 15% is where people start dying. So at best, even for a dangerously dehydrated person, drinking a lot of water is only going to boost your blood volume by a few percent: nowhere near enough to meaningfully “dilute” any toxin. BACK TO TEXT

There are limits to how much you can drink and absorb. Cholera provides a colorful example. You literally can’t drink enough water to treat cholera because you actually lose more fluid out of the rectum than you can possibly ingest to replace it. Think about that.BACK TO TEXT

There’s just not that much variation in how much filtering the kidneys can do. They are vital organs, and their work is critical to your survival, and must always proceed at a reasonable pace — even if there’s not enough fluid in the system. As with overall fluid volume, you can’t stray very far out of the normal range without getting into trouble. BACK TO TEXT